/Engine/Plugins/Editor/ObjectMixer/ObjectMixer/Source/ObjectMixer/Public/Views/List/SObjectMixerEditorList.h
bool IsTreeViewItemExpanded ( const [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [ISceneOutlinerTreeItem](API\Editor\SceneOutliner\ISceneOutlinerTreeItem) > & Row ) const